Power and free conveyor system

ABSTRACT

A power and free conveyor system that has a number of carriers and consists of a leading main free trolley and a rear subtrolley provided with a rear cam for forcing up a pusher. Pushers are attached at regular intervals to the driving chain, which is guided by the power rail. The pushers are provided with rollers and are linked to the forward tilting dog of the main free trolley. Next to the free rail, which guides the free trolley, is a subrail, upon which are both side rollers of the pusher. At a fixed point on the free rail the carrier stopper is arranged which forces up the pusher to release the engagement of the pusher and the free trolley. At carrier-diverting points are pusher-ascending rails, while on the diverting side behind the pusher ascending rail, the pusher-guiding apparatus is provided.

United States Patent [72] Inventors Takaowakabayashl [45] Patented [73] Assignee Nov. 30, 197 l Nakanishi Metal Works Co., Ltd.

Osaka, Japan [32] Priorities May 30,1968 [33] Japan [31] 43/37272;

May 31, 1968, Japan, No. 43/137131); May 31, 1968, Japan, No. 43/37131; June 3, 1968, Japan, N0. 43/38108; Aug. 30, 1968, Japan, No. 43/62532 [54] POWER AND FREE CONVEYOR SYSTEM 7 Claims, 17 Drawing Figs.

52 u.s.c1 104/172s,

104/96 511 Int.Cl B65gl7/42 [50 Fieldol'Search 104/s9,91,

Primary Examiner-Arthur L. La Point Assistant Examiner-Robert Saifer Attorney-George B. Oujevolk ABSTRACT: A power and free conveyor system that has a number of carriers and consists of a leading main free trolley and a rear subtrolley provided with a rear cam for forcing up a pusher. Pushers are attached at regular intervals to the driving chain, which is guided by the power rail. The pushers are provided with rollers and are linked to the forward tilting dog of the main free trolley. Next to the free rail, which guides the free trolley, is a subrail, upon which are both side rollers of the pusher. At a fixed point on the free rail the carrier stopper is arranged which forces up the pusher to release the engagement of the pusher and the free trolley. At carrier-diverting points are pusher-ascending rails, while on the diverting side behind the pusher ascending rail, the pusher-guiding apparatus is provided.

PAIENTEBunv 30 I9?! SHEET 1 OF 4 PATENTEUunv 30 I871 SHEET 2 [1F 4 York 1 POWER AND FREE CONVEYOR SYSTEM The present invention relates to an improved power and free conveyor system, especially a conveyor provided with a mechanism to release the engagement between the front tilting dog of a free trolley and the thrusting pusher.

It should be noted that, throughout the text of the specification and claims, the words forwards" and rearwards refer to the advancing direction of the trolley conveyor, i.e., forwards is the side of an advancing direction of the conveyor, while rearwards is the side of its reverse direction.

The power and trolley conveyor connects the driving power of the power trolley to the free trolley through the intermediary of the pusher, and when goods are transported by said conveyor, it sometimes becomes necessary to separate the carrier from the pusher of the driving chain and to temporarily stop in order to carry out loading and unloading of the goods as well as the process work, inspection and testing in the intermediate stage of the transporting process, and also to divert the carrier from one power rail to the other power rail. Hitherto, the rail section, which can be moved upward or downward by means of an oil pressure or an air pressure instrument has been provided in a section of either the power rail or the free rail, and through this arrangement, the power trolley or the free trolley has been temporarily moved vertically and, by freeing the pusher from either one of these trolleys, the carrier has been stopped. However, when such a conventional apparatus is used, the load, due to the force of the tension of the chain as well as the load of the trolley, will have influence on it. If the power rail is moved upward, while the free rail is moved upward, the load of the transported goods will fall, so it is neces sary to have a stronger oil or air pressure instrument, which naturally entails a higher cost of the apparatus.

The power rail is accompanied by the endless driving chain, and therefore must also have an endless structure. The free rail can be made to extend straight over a long distance in conformity with the objects of transportation, however, the carrier must be diverted from the first power rail to the second power rail. Hitherto the first power rail has been bent upward in order to release the pusher from its engagement with the tilting dog of the free trolley. However, in order to send the carrier, which has lost the advancing power received from the pusher, to the second power rail, a special cylinder or feeder has been provided, and the speed of the driving chains on both power rails had to be synchronized.

One of the objects of the present invention is to provide an apparatus which can easily stop any required number of carriers successively. Thus, there is no need for a section which can temporarily move either the power rail or the free rail upward or downward.

Another object of the invention is to provide an apparatus which allows the carrier to be diverted from one endless power rail to the other endless power rail, even when the speeds of the conveyors of both rails are different from each other.

Still another object of the invention is to maintain a stable condition of engagement between the free trolley and its thrusting pusher at all times during the movement of the carrier, even at the down grade section of the conveyor line.

Yet another object of the invention is to provide an apparatus which can gather the carriers even at a curved section of the conveyor line.

In short, the power and free conveyor system according to the present invention comprises a power rail, a free rail which is arranged beneath said power rail at a suitable interval, a driving chain suspended from the power trolley, which rolls on the power rail, a free trolley, which rolls on the free rail and which is provided with front and back tilting dogs, a pusher with rollers on both sides which can freely move vertically, and which is connected to the driving chain that engages the front tilting dog of said free trolley, and a subrail, upon which roll the rollers of the pusher, arranged on the free rail.

The carrier comprises the leading main free trolley which has a pair of tilting dogs, and the rear subfree trolley, which is coupled to the main free trolley and which is provided with a cam for forcing up the pusher, at the rear end of which is formed a U-shaped notch which can freely rotate horizontally.

At a fixed point of the free rail a stopper is provided which forces up the pusher to release its engagement with the free trolley.

Other objects and advantages of the apparatus according to the present invention with regard to its constitution and operation will become clearer by reference to the accompanying drawings and the detailed description in connection thereto, wherein:

FIG. 1 is the partly broken side view of the new power and free conveyor of the invention equipped with the carrier pusher.

FIG. 2 is a sectional view taken along the line of 22 of FIG. 1.

FIG. 3 is also a sectional view FIG. 1.

FIG. 4 is a partial side view the carriers.

FIG. 5 is a horizontal sectional view showing the gathering state of the carriers at the curved section of the conveyor line.

FIG. 6 is a horizontal sectional view of a reference example showing a state wherein the carriers cannot be gathered at the curved section of the conveyor line.

FIG. 7 is an enlarged sectional view taken along the line of 7-7 of FIG. 2.

FIG. 8 is an explanatory plan showing the necessity of gathering the carriers at the curved section of the conveyor line.

FIG. 9 is a vertical sectional view of the movement of car riers at the down grade section of the conveyor line.

FIG. 10 is a sectional view taken along the line 10-10 of FIG. 9.

FIG. 11 is a partial longitudinal section of a reference example of the down grade section of the conveyor line same as FIG. 9, where there is no upper subrail.

FIG. 12 is a side view of the pusher pressing down apparatus to be used when switching the carrier from one endless power conveyor to the other endless power conveyor.

FIG. 13 is the sectional view taken along the line of 13-13 of FIG. 12.

FIG. 14 is a diagrammatical the carrier from one endless power rail.

FIG. 15-17 are diagrammatical side view showing the switching operations of the above-mentioned carrier.

Reference is now made to FIGS. 1-3, wherein the horizontal power rail 1 is made of steel material, and is square in cross section with a longitudinal slit 2 in the central part of the bottom wall. A power trolley 3 is provided with rollers 4 on the left and right sides, and another pair of rollers 6 are also arranged on the left and right sides. There is a pair of rollers for every fixed number of trolleys 3 on the power rail 1. Because of the slit 2 in the power rail 1, the trolley 3, by means of the rollers, can freely roll on power rail 1. The endless driving chain 7 arranged beneath the power rail 1 is made to move constantly in the direction of the arrow shown in FIG. 1 by the motor and the conductive means which are not illustrated, while the trolleys 3 and 5 are coupled thereto at a fixed interval. 0n the lower end of the trolley 5 is a bracket 8 of a reverse U-shape in cross section, which projects backward and angularly downward, against which the pusher 9 is fixed to project forward and angularly downward, by means of a pivot 10 to allow free swing, and is constantly pressed downward by the push spring 11. On the rear section of the upper side of the pusher 9 is a projection 12 which extends beneath the lower side of the upper wall of the bracket 8, and when the pusher 9 tends to hang down further from a certain point, said projection 12 will strike against said bracket lower side to interrupt the pusher 9 limiting the action of the pusher. On both sides of the lower end of the pusher 9 are two rollers 13, 14 inside and outside.

taken along the line 3-3 of showing the gathering state of plan of the apparatus to switch power rail to the other endless A free rail 15 is provided at a suitable interval below the power rail 1 and is constructed by using pairs of steel elements in a lateral U-shape. It is connected to the power rail 1 by a coupling frame 16 which is arranged at a fixed interval.

The carrier C includes a leading main free trolley 20, which has a pair of tilting dogs l8, l9, and two intermediate free trolleys, which are respectively provided with a hanger 24 and are fixed to the lower end of said main free trolley by a pivot 23 so as to freely swing. The respective free trolleys 20, 22 and 25 have a pair of vertical rollers 38 in the front and the rear of the point of the rail housing 150 on the free rail 15, where the rollers 38 are received and a horizontal roller 17 which rolls along the side of the rail housing 150. Free trolleys 20, 22 are connected by a connecting rod 30 and are provided with a downward projecting piece 26 by means of the pivot 27. The downward projecting piece 26 and the hanger 24 are provided with short and horizontal projections 26a and 24a to which are respectively arranged a forked joint 28 by means of a pivot 29 so as to freely swing vertically. A U-shaped section 300, is provided at both ends of the connecting rod 30. Said U-shaped section 300 is fastened by means of pivot 31 so as to swing freely left and right. It is not necessary to provide an intermediate free trolley. The hanger 24 may be arranged to the main and subfree trolleys without an intermediate free trolley. The tilting dogs 18, 19 are fixed to the trolley 20 in such a way that they can both come down inwardly by means of pivot 27 and they can stand upright by their dead load. Cam 21 is U- shaped with a bottom plate 210 and a sidepiate 21b which forms a cam surface, while its latter half projects out behind the subfree trolley 22. At the center of the rear section of the bottom plate 21a is a U-shaped notch 32, the entrance of which is slightly opened. On the upper surface of the subfree trolley 22 is a mount 33 for the cam 21, which is fixed to said mount by means of bolt 34 and freely rotates horizontally. On the bottom plate 210 of the cam 21 is a long hole 35 through which another bolt 36 is fixed to mount 33. On both sides of the free rail 15, which is the main rail, is welded a subrail 37 which projects slightly higher than free rail 15, and receives outside roller 14 of pusher 9. Subrail 37 is a flat band vertically erected. It can be of any shape as long as it will receive the roller 14. The carrier stopper S is arranged on the same level as carrier stopper S consists of a force plate 39 which is of polygon shape, an upper side 39a which is horizontal and located on the same horizontal plane as the upper end of the subrail 37, a first inclined side 39b and a second inclined side 39c making an obtuse angle, and is fixed to the back side of the lower end of the connecting rod 16. It is fixed to bracket 40 by means of pivot 41 to freely rotate. On the lower section of force plate 39 is a stop pin 42 projecting inward. It is made to come out on the moving line of the pin 43 which is arranged to the free trolley 20 to project outward, when ascending, as will be hereafter explained. On the power rail 1, the base 44 is fixed to the corresponding position of the force plate 39, and to this base 44 is fixed an air cylinder 45 by a fixture 46. in front of the air cylinder 45 is fixed the bearing 48 of the crank shaft 47. To the crank shaft 47 are fixed a front link 49 and a back link 50, which constitute a bell crank with both ends and center respectively. The end of the back link 50 is fixed to the end of rod of the air cylinder 45 by means of pivot 52 to freely swing, while the end of the front link 49 is connected by means of pivot 54 to the connecting rod 53 vertically erected on the outside of the force plate 39. The subrail has a cut section 76 in order not to impede the operation of the force plate 39.

As shown by FIG. 1, the carrier C C moves in the direction of the arrow together with the driving chain 7 by linking the pusher 9 to the front tilting dog 18 of the leading main free trolley 20. Although not illustrated, many carriers follow the preceding carrier in the same way at a predetermined interval, which is determined by the interval of the pusher 9 hanging down from the driving chain 7. In order to stop the carriers 17 which are moving in succession, the air cylinder 45 is activated to push out the rod 51, so that the force plate 39 will rotate counterclockwise for an angle 61 with the pivot 41 as a center, as shown by the chain line of FIG. 1. Consequently, the first inclined side 39b will stand up horizontally and extend higher than the subrail 37 to reach a height at least over the tilting dogs l8, 19. In the front and back of the first inclined side 39b, which has become horizontal, the upper side 39a and the second inclined side 39c appear above the subrail 37 in an inclined connection, and the main free trolley 20 of the carrier C,, which is advancing first, will move along the interior side of the force plate 39. Rollers 14, which are on both sides of the pusher 9 linked to the front tilting dog 18, will roll along the force plate 39, so that the pusher 9 will ascend against the force of push spring 11 and separate itself from the front tilting dog 18, and the pin 43 of the main free trolley 20 will strike against the stop pin 42 of the force plate 39 and the first advancing carrier C, will stop. The first advancing carrier mentioned above is used in this instance to mean the carrier which is the first one to be stopped among many moving carriers. When the first carrier is stopped, the second and succeeding carriers are still moving together with the driving chain 7, and the front tilting dog 18 of the main free trolley 20 of the second carrier C2 will enter into the notched section 32 of the cam 21 of the subfree trolley 22 of the first carrier Cl and pusher 9 which is linked to the front tilting dog 18 will come off said tilting dog 18 and pass along the front of subfree trolley 22, as the push spring 11 ascends, since the rollers 14 on both sides of the pusher 9 roll up along the sideplate 21b of the cam 21, and as a result, the second carrier C will stop next to the first carrier C, (See FIG. 4). Said pusher 9 still continues to advance and ascends again at the point of the force plate 39 to go over the main free trolley 20 of the first carrier In this way, the driving chain 7 with the pusher 9 will continue to move, while the third and the succeeding carriers for transporting the goods will successively stop and accumulate In order to again move the group of accumulating carriers, the stopper must be restored to its original condition. Pusher 9 which came from behind, will push down forward, and back tilting dog 19 of the main free trolley 20 will be linked to the front tilting dog 18, so that the first carrier C. will start to advance together with the driving chain 7, and the back tilting dog 19 will be restored to its original condition by its dead load, after pusher 9 has passed. When the first carrier C, moves, its subfree trolley 22 will come off the main free trolley 20 of the second carrier C which is stopping them, together with the cam 21. Consequently, the second positioned pusher will be linked to the front tilting dog 18 of the main free trolley 20 and the second carrier C will be forced to advance. in this way, all the carriers which have been stopped will successively start at intervals between the respective pushers. The force plate 39 in the above-mentioned example of the invention assumes a form to rotate to push up the roller 9, and it will be noted that it can be made to bring up and down the force plate which has a horizontal section and the inclined section before and behind the former section, and since the carrier C will stop, if the pusher 9 is removed from the tilting dog 18, when the conveyor moves at a low speed, it is not necessary to arrange the stop-pin 42 as well as the pin 43.

Both the power rail l and the free rail 15 are fixed to the upper and lower positions respectively by means of the connecting frame 16 as and, because there will be manufacturing errors in the interval H (See FIG. 3) between these two rails, said interval cannot remain the same at all points. Consequently, if there is no subrail 37 and only the pusher 9 hangs down, the interval it between the pusher 9 and the free rail will become irregularly larger or smaller. When it becomes larger, there is no trouble. But, if it becomes smaller, the pusher will not ascend, since the roller 14 of pusher 9 will cut into the rear end of the sideplate 21b of the cam 21, because there is a gap between the lower side of the cam 21 and the upper side of the free rail 15, when a group of carriers are stopped. The rear end of the side plate 21b of the cam 21 is pointed, and when there is resistance to the pusher 9, it tends to descend, as

shown in the drawing. As a result, the coupling between the pusher 9 and the tilting dog 18 cannot be released. However, in the power and free conveyor system according to the present invention, the pusher 9 is arranged to the driving chain 7 and freely moves vertically, while both sides are provided with rollers 14, and on both sides of the free rail are fixed the subrail 37 projecting out slightly above said free rail 15, so that the rollers 14 of the pusher 9 can roll along said subrail. As a result, as can be seen from FIG. 3, the gap h between the rollers 14 and the free rail 15 will always be constant and the coupling state of the pusher 9 and the tilting dog will also be kept constant at all times. Consequently, when the carriers C are stopped, the coupling between the pusher 9 and the tilting dog 18 will be smoothly released.

Reference will now be made to FIGS. 5-8, wherein the group of carriers C is stopped at the curved section of the conveyor line, i.e., the curved section 55 of the free rail 15, the cam 21 of the carrier C, swings to the extent of an angle 02 from the center line 55 of the subtrolley 22 and its notch 32 cannot come ofi the opposite gap of a pair of the free rails 15, as shown by FIG. 5, because the cam 21 of the preceding carrier C, can freely swing horizontally with pivot 34 as its supporting point, and there is the subrail 37 in the free rail 15. Consequently, the tilting dog 18 of the main free trolley of the second positioned carrier C, will enter into said notch 32 and it can stop in the condition of above-mentioned FIG. 4. If cam 21 is fixed firmly and there is no subrail 37, carrier C will be in the condition as shown by FIG. 6. In other words, since the cam 21 always coincides with the centerline of the subfree trolley 22, the notch 32 will come off the opposite gap 57 of the free rail 15, and the rear section of the cam 21 which is projecting out will come into gap 57. As a result, the front tilting dog 18 of the main free trolley 20 of the second positioned carrier C, will collide with the rear section of said cam 21 and the rollers 14 of the pusher 9 cannot roll up along the sideplate 21b of the cam 21. Therefore, the coupling between the tilting dog 18 and the pusher 9 cannot be released, and in the curved section 55 of rail 15, there will be no accumulation of carriers. This has several disadvantages.

When goods are to be transported by the power and free conveyor, the carrier must be separated from the pusher of the driving work, inspection and testing of the goods in the intermediate works in the transportation from loading to unloading, so that carriers will accumulate. In order to utilize space advantageously, it is desirable that, as shown by FIG. 8, the rails I and 15 are meandering. But if the carriers cannot be accumulated at the curved section 55, they will be accumulated only in the straight section as illustrated. Consequently, when converting the leading carrier C, for transportation in the second row from the bottom of FIG. 8 to the first row, it can be carried out only after detecting, by the use of such detectors 58 as the photoelectric tube apparatus or the limit switch, that the leading carrier C, in the first row has been already sent out and the carrier C, at the rear of the same row has been shifted one step forward. However, the interval between the carriers C I and C, depends upon the accumulating conditions of the carriers; it may be long on one occasion and short on the others. In other words, since there will be a delicate difference in the stopping gap of the mutually adjacent carriers because of the difference in the operating speed of the driving chain 7 and the load of the carriers, the stopping place of the last carrier C, of the straight row cannot always be uniform. Consequently, it sometimes happens that, though the carrier C, is still remaining in said row, a signal telling its departure will be flashed. The leading carrier C of the second row from the bottom of FIG. 8 will move to contact the preceding carrier C,, then both carriers C, and C will be in the condition as shown in FIG. 6 and, as the coupling of the tilting dog 18 and the pusher 9 is not released, the driving chain 7 will be broken, and thus the stoppers of the carriers will be arranged at their advancing ends of the respective straight lines for accumulating sections. There are no such disadvantages in the power and free conveyor system of the present invention.

As shown in FIGS. 9-11, in the down grade section 59 of the conveyor line, the upper subrail 60 is arranged with a fixed gap above the lower subrail 37, Le, slightly above the moving locus of the roller 14 of the pusher 9, both parallel, and it is welded to the supporting element 61 to project out inside the connecting frame 16.

While the accumulation of the carriers C will be effected as above-mentioned, the pusher 9 and the main free trolley 20 should not be separated during the movement of the carriers C.

In the power and free conveyor according to the present invention, the pusher 9 is arranged to the power trolley 3, which drives along the power rail 1, to freely swing and to project forward and angularly downward. As a result, in the horizontal section and the rising gradient of the conveyor line, the pusher 9 is firmly coupled to the front tilting dog 18 of the main free trolley 20 as shown by FIG. 1 and it will never come off, because when there is a resistance in the advancing pusher 9, a downward moment will be generated. Since the pusher 9 is arranged forward and angularly downward to freely swing, so that its coupling with the front tilting dog 18 will become steadier especially in case of a rising gradient. If the pusher 9 is reversely arranged to freely swing vertically or backward and askant downward, an upward moment will be generated, then there is a resistance in the advancing pusher 9, and it tends to come off the front tilting dog 18. On the other hand, if the pusher 9 is fixed vertically as in a conventional system, the above-mentioned accumulating operation of the carriers cannot be carried out.

However, when the pusher 9 is arranged to freely swing forward and angularly downward, it will act excellently as above mentioned, in the horizontal section and the rising gradient section of the conveyor line. However, there will be a problem in case of a falling gradient as follows:

As the speed of the carrier C becomes higher than the driving chain 7 by the gravity of the load suspended from the hanger 24, the pusher 9 will be coupled to the rear tilting dog 19 of the main free trolley 20. As a result, the pusher 9 will be pushed from behind by the rear tilting dog 19 and the upward movement will be generated. If there is no subrail 60, the pusher 9 will rotate clockwise as shown in FIG. 11 and it will come off the tilting dog 19, so that there will be a danger that the pusher 9 alone will run by itself. In this respect, however, the power and free conveyor system of the present invention provides the upper subrail 60 slightly above the moving locus of the roller 14 arranged on the side of the pusher 9 in parallel to the free rail 15 in the falling gradient. Therefore, the roller 14 will be pressed down from above to firmly prevent the pusher 9 from getting away and impedes the carrier C to run by itself.

In FIGS. 12 and 13, is shown the pusher-guiding means P provided above the moving line of the outside roller 14 of the pusher 9. Said pusher guiding means P is constituted by the upper plates 63 which are bilateral and cross-sectionally reverse U-shaped and which are welded to the supporting elements 62 which have a cross-sectional L-shape and which are fixed to the connecting frame 16, the lower plates 64 which are provided beneath the respective upper plates 63 at a fixed interval, the laterally U-shaped connecting elements 67 which connect the lower plates 64 to the upper plates 63 by means of the pivots 65, 66 to freely move up and down, and the coiled tension spring 71 spanned between the adjusting bolt 69 fixed to the fitting 68 vertically attached to the lower surface of the upper plate 63 and the shaft 70 provided below the center of the connecting element 67. At the front and rear ends of the lower plate 64 are formed the roller leading-in gradient section 64a and the roller discharging gradient section 64b to extend upward from the horizontal section of the lower plate 64 respectively.

In FIG. 14, are shown the first and second pusher ascending rails 72 and 73, which are formed by oppositely facing the cross-sectional L-shaped steel pieces. They are both made to coincide respectively with the curves of the first power rail 74 and the second power rail 75, both of which are shown by the centerlines, and they are positioned at the height where the pusher 9 can be separated upward from the tilting dog 18 of the main free trolley 20. At the front and rear ends of the first pusher-ascending rail 72 are respectively formed the roller leading-in gradient 72a and the roller-discharging gradient section 72b. Likewise at the front and rear ends of the second pusher ascending rail 73 are formed the roller leading-in gradient section 73a and the roller discharging gradient section 73b. All these gradient sections 72a, 72b, 73a and 73b extend downward from the horizontal sections of 72 and 73. The roller leading-in gradient 72a of the first ascending rail 72 is positioned behind the curve initial point A, while the roller discharging gradient 73!; of the second ascending rail 73 is before the curve terminal point B. The lower plate 64 of said pusher leading-in apparatus P has a length greater than the interval between the curve initial point A and the curve terminal point 1B.

The converting operation of the carrier C from the first ascending rail 72 to the second ascending rail 73 will be described by making reference to FIGS. -17, as follows:

The force plate 39 of the stopper S is returned from the ascending position in FIG. 15 to the descending position in FIG. 16, then the advancing pusher 9 will catch the front tilting dog 18 of the main free trolley 20 of the carrier C and advance. As soon as the main free trolley 20 passes the stopper S, the force plate 39 will be immediately returned to the ascending position and the second positioned carrier will be stopped. Meanwhile, said main free trolley 20 will be moved by the pusher 9 to the first pusher-ascending rail 72, as shown by FIG. 15. But, at this point, the rollers 13, 14 of the pusher 9 will be led into the roller leading-in gradient section 72a and move upward, so that the coupling between the pusher 9 and the tilting dog 18 will be released and the rollers 13, 14 of the pusher 9 will roll up the first pusher ascending rail 72 and turn in accordance with the curve of the first power rail 74. On the other hand, as the carrier C will stop at the aforesaid position, the cam 21 of the subfree trolley 22 will remain at the position where there is the pusher leading-in apparatus P. When things are in this condition, the second positioned pusher 9 advances and its inside roller 13 collides with the rear end of the cam 21 and slightly ascends along its sideplate 21b. As the outside roller 14 will then collide with the lower plate 64 of the pusher leading-in apparatus P, the pusher 9 will not ascend further, and since the outside roller 14 rolls counterclockwise, while the inside roller 13 rolls clockwise and pushes the cam from behind, the carrier C will advance, as shown by FIG. 16, and its main free trolley 20 will come before the roller-discharging gradient section 73b. When it is in this condition, the pusher 9 of the second power rail 74, which has been sent along the second pusher-ascending rail 73, will come down from the roller-discharging gradient section 73b to be coupled to the tilting dog 18 of said trolley 20 and I force the carrier C to come within the scope of influence of the second power rail 75. In this way, the converting operation of one carrier is completed, and any number of carriers can be converted in like manner.

In the above-mentioned example of the invention, the stopper S is arranged behind the pusher leading-in apparatus. But, when the speed of the conveyor on the side of the second power rail is greater than that of the conveyor on the side of the first power rail 74, it is difficult for the respective pushers 9 on the side of the second power rail 75 to catch the tilting dogs 18 of the main free trolley 20 in succession, and there is no need to control the leading-in operation of the carrier C. Consequently, there is no need to provide the stopper in such a case. However, when the speed of the conveyor on the side of the second power rail 75 is lower than that of the conveyor on the side of the first power rail 74, because the length of the carrier C is not the same as the pitch of the pusher 9, the pusher will not catch the tilting dog 18 of the carrier soon enough, in which case, it becomes necessary to stop the carrier C once and control the leading-in operation to the side of the second power rail 75.

Besides, in the above-mentioned example, the pusher leading-in apparatus P is so constituted that, through the intermediary of the connecting lever 67, which can freely swing, the lower plate 64 can move upward. But, when a group of carriers C is stopped and accumulated on the second power rail 75, trouble will occur, if the cam 21, which is in the position of the pusher leading-in apparatus P, is forcibly pushed from behind. Therefore, it has been arranged so that pusher 9 can move upward, and if there is no accumulation of carriers, lower plate 64 will be firmly fixed.

Further, in the above example, when one of the connecting elements 67 is extended upward to pass through the upper plate 63, the rod of the air cylinder is arranged to come from the opposite side of the tension spring, and projected out when the leading-in operation is not carried out, and the connecting elements 67 will be inclined further in resistance to the tension spring so that the lower plate 64 will ascend and the pusher 9 will move beyond the cam 21.

According to the power and free conveyor system of the invention, the carrier can be smoothly converted, by a simple apparatus such as above-mentioned, from one endless power rail to the other endless power rail without difficulty.

We claim:

1. A conveyor traveling along a conveyor line comprising in combination, a power rail, a free rail which is provided beneath said power rail in parallel there-to and at a suitable interval therefrom to allow added components to pass through between both of said rails, a conveying means with rollers provided with a movable cam in contact with said free rail and which can freely move along said rail, when coupled, and which is arranged above said free rail, a power trolley below said power rail comprising rollers which movably contact with said power rail for the movement of said trolley below said rail, a moving means connected with said trolley in order to make said trolley move along said power rail, a lever means on said trolley comprising a pusher which can freely move vertically and is arranged below said power rail to be coupled to a coupling means and which is provided with rollers, at least on one side, which combine said power trolley and a conveying means in order to move it together with said power trolley, and a subrail which is arranged at least on one side of said free rail to project slightly upward from said rail in order to steadily keep up the coupling state between said pusher and said free trolley, and which guides said rollers of said pusher, an upper guide rail arranged in a falling gradient section of the conveyor line and above said subrail at a suitable interval in order to prevent said rollers on at least said one side of said conveyor line which move along said free rail from escaping upward, a bracket, upon which are arranged lever means for a predetermined number of power trolleys connected with said moving means and which is firmly fixed to the lower end of said trolley to extend backward and angularly downward, and a pusher which is fixed to said bracket by a pivot to freely swing and extends forward and descendingly downward.

2. In a conveyor having:

a. a power rail (1) held in space and generally disposed parallel to the surface beneath said rail;

b. a free rail (15) under said power rail and parallel thereto, disposed at a suitable distance therefrom so that additional components can pass therebetween;

c. at least one conveying means (20) with rollers (38) movably connected to said free rail (15), for free movement therealong beneath said rail;

. coupling means (l8, 19) arranged above and connected to said conveying means which when engaged will then move said conveying means along said rail;

e. a power trolley (5) mounted under said power rail (1) including rollers movably connected to said power rail for movement of said trolley under said rail;

f. moving means (7) connected with said power trolley (5) for moving said trolley along said power rail (1 g. lever means on said power trolley including a pusher (9) with rollers (13, 14) disposed under said power rail (1) to engage said coupling means (l8, 19) for linking said power trolley and said conveying means so as to move said conveying means with said power trolley; a bracket (8) in which are disposed said lever means firmly fixed to the lower end of said power trolley to extend backward and angularly downward, said pusher being fixed to said bracket by a pivot to freely swing and extends forward and angularly downward; subrails (37) which coupling state between said pusher and said free trolley by guiding said rollers (l3, 14), said rollers normally rolling on said subrails;

i. a stopper having a pusher force plate (39) with an upper end (39a) coinciding with a moving locus of the lower end of one of said rollers (13, 14) in a normal condition with said main free trolley at the rear end section of which is a cam element (21) having a U-shaped notch (32), said cam element being fixed to said subfree trolley so as to swing horizontally at the curved section of the conveyor line along the inner side of said subrail. 3. A conveyor as claimed in claim 2, wherein said pusher force plate (39) has a polygon shape and can freely rotate, while in said subrail with an upper side in the same horizontal plane as the upper end of the subrail, a first gradient side and a second gradient side, making a obtuse angle, and when said pusher force plate is rotated for a fixed angle, the first gradient side rises up to be horizontal to project above said sub-rail and is positioned at a height over said tilting dogs (l8, l9).

4. A conveyor as claimed in claim 3, including a pressure 

1. A conveyor traveling along a conveyor line comprising in combination, a power rail, a free rail which is provided beneath said power rail in parallel there-to and at a suitable interval therefrom to allow added components to pass through between both of said rails, a conveying means with rollers provided with a movable cam in contact with said free rail and which can freely move along said rail, when coupled, and which is arranged above said free rail, a power trolley below said power rail comprising rollers which movably contact with said power rail for the movement of said trolley below said rail, a moving means connected with said trolley in order to make said trolley move along said power rail, a lever means on said trolley comprising a pusher which can freely move vertically and is arranged below said power rail to be coupled to a coupling means and which is provided with rollers, at least on one side, which combine said power trolley and a conveying means in order to move it together with said power trolley, and a subrail which is arranged at least on one side of said free rail to project slightly upward from said rail in order to steadily keep up the coupling state between said pusher and said free trolley, and which guides said rollers of said pusher, an upper guide rail arranged in a falling gradient section of the conveyor line and above said subrail at a suitable interval in order to prevent said rollers on at least said one side of said conveyor line which move along said free rail from escaping upward, a bracket, upon which are arranged lever means for a predetermined number of power trolleys connected with said moving means and which is firmly fixed to the lower end of said trolley to extend backward and angularly downward, and a pusher which is fixed to said bracket by a pivot to freely swing and extends forward and descendingly downward.
 2. In a conveyor having: a. a power rail (1) held in space and generally disposed parallel to the surface beneath said rail; b. a free rail (15) under said power rail and parallel thereto, disposed at a suitable distance therefrom so that additional components can pass therebetween; c. at least one conveying means (20) with rOllers (38) movably connected to said free rail (15), for free movement therealong beneath said rail; d. coupling means (18, 19) arranged above and connected to said conveying means which when engaged will then move said conveying means along said rail; e. a power trolley (5) mounted under said power rail (1) including rollers movably connected to said power rail for movement of said trolley under said rail; f. moving means (7) connected with said power trolley (5) for moving said trolley along said power rail (1); g. lever means on said power trolley including a pusher (9) with rollers (13, 14) disposed under said power rail (1) to engage said coupling means (18, 19) for linking said power trolley and said conveying means so as to move said conveying means with said power trolley; a bracket (8) in which are disposed said lever means firmly fixed to the lower end of said power trolley to extend backward and angularly downward, said pusher being fixed to said bracket by a pivot to freely swing and extends forward and angularly downward; h. subrails (37) which are arranged on both sides of said free rail projecting slightly over said rail to maintain the coupling state between said pusher and said free trolley by guiding said rollers (13, 14), said rollers normally rolling on said subrails; i. a stopper having a pusher force plate (39) with an upper end (39a) coinciding with a moving locus of the lower end of one of said rollers (13, 14) in a normal condition and which will project upward from said locus when said lever means is released from said coupling means so that at least one of said conveying means will be stopped, the improvement therein wherein: j. said coupling means includes a leading main free trolley which has a pair of tilting dogs (18, 19) engaged by said pusher (9) and a rear subfree trolley which is connected with said main free trolley at the rear end section of which is a cam element (21) having a U-shaped notch (32), said cam element being fixed to said subfree trolley so as to swing horizontally at the curved section of the conveyor line along the inner side of said subrail.
 3. A conveyor as claimed in claim 2, wherein said pusher force plate (39) has a polygon shape and can freely rotate, while in said subrail with an upper side in the same horizontal plane as the upper end of the subrail, a first gradient side and a second gradient side, making a obtuse angle, and when said pusher force plate is rotated for a fixed angle, the first gradient side rises up to be horizontal to project above said sub-rail and is positioned at a height over said tilting dogs (18, 19).
 4. A conveyor as claimed in claim 3, including a pressure cylinder means disposed over said power rail, a bell crank lever, a connecting lever, and a rod connecting said pressure cylinder means and said force plate so as to rotate said force plate.
 5. A conveyor as claimed in claim 4, including a second power rail, said first and second power rails having curved sections and a converting point, a first pusher ascending rail with roller leading-in gradient sections and roller-discharging gradient sections respectively provided along and above said curved sections of said rails, a pusher leading-in means behind said first pusher-ascending rail, but above said first free rail and at an interval slightly wider than the diameter of said rollers of said pusher.
 6. The conveyor as claimed in claim 5, including a fixed upper plate of said roller leading-in means, a movable lower plate which is arranged at a fixed interval from said fixed upper plate and which said rollers of said pusher contact and a spring which constantly presses down on said lower plate.
 7. The conveyor according to claim 5, wherein said pusher has inside and outside rollers, and the inside roller pushes the rear end section of said cam, while the outside roller contacts said roller leading-in means. 